LED HYBRID PATHWAY LIGHTING for The National Park Service

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1 Design and Engineering Services LED HYBRID PATHWAY LIGHTING for The National Park Service PRELIMINARY TECHNOLOGY ASSESSMENT Statewide Emerging Technologies Funding Program Prepared by: Design and Engineering Services Customer Service Business Unit Southern California Edison October, 2005

2 Project Management This project was managed by Henry Lau, PE, and Vireak Ly of Southern California Edison. For more information on this project, Acknowledgements Southern California Edison s Design & Engineering Services group is responsible for this project. It was developed as part of Southern California Edison s Emerging Technology program. Disclaimer This report was prepared by Southern California Edison and funded by California utility customers under the auspices of the California Public Utilities Commission. Reproduction or distribution of the whole or any part of the contents of this document without the express written permission of SCE is prohibited. This work was performed with reasonable care and in accordance with professional standards. However, neither SCE nor any entity performing the work pursuant to SCE s authority make any warranty or representation, expressed or implied, with regard to this report, the merchantability or fitness for a particular purpose of the results of the work, or any analyses, or conclusions contained in this report. The results reflected in the work are generally representative of operating conditions; however, the results in any other situation may vary depending upon particular operating conditions. Southern California Edison Page 2 of 13

3 INTRODUCTION The LED hybrid fixture described within this report was developed by the California Energy Commission s Public Interest Energy Research (PIER) Program. PIER supports energy research, development and demonstration projects which aspire to bring energy efficient products to the marketplace. This hybrid fixture combines light emitting diode (LED) technology with incandescent lighting which is driven by an occupancy sensor. Darkness turns on the LEDs to provide general, low-level light and to act as a marker for light fixture recognition at a distance. When motion is detected through the on-board occupancy/light sensor, the incandescent light turns on. After a few minutes of vacancy, the light turns off again leaving the LEDs on. The fixture can also substitute a fluorescent for an incandescent, when appropriate. It was designed for a porch light application. TECHNOLOGY DESCRIPTION The LED hybrid lighting technology promises to replace residential, commercial, and industrial porch lights, pathway lighting, and security lighting. The LED provides 20 lumens/watt illumination and offers much longer life than that of its traditional incandescent counterparts. There are a number of benefits associated with the installation of LED hybrid exterior lighting systems. A sample of the estimated annual operating kw and annual savings in kwh in comparison with existing lighting systems for this application is shown below. Base Case 1: 60W Incandescent Lamp on 12 hours a night = 720Wh per nightbase Case 2: 13W Compact Fluorescent Lamp on 12 hours a night = 156Wh per night New Technology Case 1: 60W Incandescent Lamp on 12 hours a night w/ 2 hour occupancy = 5 W *12h + 60W = 120Wh per night New Technology Case 2: 13W Fluorescent Lamp on 12 hours a night w/ 2 hour occupancy = 5 W *12h + 13W = 73Wh per night *12 hours of darkness per night assumed. *2 hour occupancy per night assumed. The yearly energy use calculation based on the assumptions is shown in Figure 1. Southern California Edison Page 3 of 13

4 Case Lamp Nightly Energy Use (Wh) Yearly Energy Use (kwh) Base 1 60W Inc New 1 60W Inc Base 2 13W CFL New 2 13W CFL 73 Figure 1: Yearly Energy Use Figure 2 shows the percent energy savings when going from one technology to another. Going From To Before (kwh) After (kwh) Savings 13W CFL 13W CFL % 13W CFL 60W Incandescent % 60W Incandescent 60W Incandescent % 60W Incandescent 13W CFL Figure 2: Percent Savings 89.86% Figure 3 shows the total energy saved for a year with the assumptions of 12 hours of night, 2 hours of occupancy per night, and 55,000 fixtures in use. Going From To Before (kwh) After (kwh) Energy Reduction/ Fixture (kwh) Number of Fixtures Total Energy Saved (kwh) 13W CFL 13W CFL ,000 1,666,225 13W CFL 60W Incan , ,700 60W Incan. 60W Incan ,000 12,045,000 60W Incan. 13W CFL ,000 12,988,525 Figure 3: Total Energy Saved per Year *55,000 fixtures assumed. Figure 4 shows the night time demand reduction. Going with the above assumptions, there would be a total of 440kW to 3,025kW night time demand reduction, which is about a 60% to 90% reduction in night time demand. Before After (W) Difference (W) Number of Fixtures Demand Reduction (kw) % Reduction 13 W CFL , % 60 W Incan ,000 3, % Figure 4: Demand Reduction *Main lights assumed off most of the time w/ only LEDs on Southern California Edison Page 4 of 13

5 STATEMENT OF WORK The National Park Service was interested in installing the hybrid LED pathway lights for the Wuksachi Lodge area in Sequoia National Park. The lodge is located on the western slope of the Central Sierra at 7,200 feet above sea level and is open year-round. During the winters the area experiences freezing cold temperatures and heavy snow. An onsite meeting and survey with Gail Vize, Southern California Edison Account Executive, and Jack Vance, Sequoia National Park Director of Facilities, brought up several issues that needed to be addressed before moving forward with the project. They were: What is the area and range of the occupancy sensor coverage? Can the LED hybrid outdoor fixtures provide sufficient/equivalent lighting to that of the existing incandescent fixtures? Occupancy Sensor Coverage Area and Range Testing The occupancy sensor coverage range was found to be insufficient for pathway lighting at Sequoia National Park. The fixture s range was tested by walking toward it at various angles at 15 degree increments. The sensor did not trigger the incandescent lamp until a distance of only a few feet from the light was reached. With a mounting height of 4 feet, the occupancy sensor triggers the main lighting at an average of about 3.3 feet. The longest range measured in the test was about 7 feet. Figure 5 provides a diagram of the detection points. In the diagram, the fixture is located at the origin facing upwards at 0. Southern California Edison Page 5 of 13

6 Figure 5: Detection Point Locations While Walking Towards the Fixture After further research for the cause of the sparse occupancy pattern, it was discovered that the fixture s occupancy and light level sensor was not designed for outdoor ranges. According to the Coverage Pattern section of the manufacturer s sensor manual, the sensor was originally designed for indoor ceiling-mounted applications. The lens was designed to be mounted about 8 feet high and 6 feet away from the occupant. As the distance from the sensor increases, the sensitivity would decrease drastically. Figure 6 provides the manufacturer s occupancy sensor coverage pattern specification sheet for the specific sensor. Southern California Edison Page 6 of 13

7 Figure 6: Manufacturer s Occupancy Sensor Specification Sheet Southern California Edison Page 7 of 13

8 CONCLUSIONS The LED hybrid lighting system cannot provide sufficient/equivalent lighting on a 1-to-1 basis. The current pathway lights are about 4-feet high with translucent lenses on all four sides. This design provides 360 of general illumination and long-range marker visibility. Figures 7 and 8 show an example of the currently installed pathway lights, and the hybrid LED pathway light, respectively. Figure 7: Current Pathway Light Figure 8: LED Hybrid Pathway Light The LED hybrid pathway fixture was designed to be more directional than the current fixtures. Figure 9 shows a ground illuminance map for the LED hybrid fixture with the incandescent light on which demonstrates this lack of multi-directionality. Southern California Edison Page 8 of 13

9 Figure 9: Ground Illuminance Map for Hybrid LED Pathway Light As can be seen from this ground illuminance map, the hybrid LED fixture illuminated the area in front of it far greater than area behind it. The white box represents the mounting pedestal used. The actual hybrid LED fixture is right above the red and brightest part of the graph. The fixture was mounted 4 feet off the ground to match the height of the fixtures currently in use at Sequoia National Park. For the test, the pedestal on which the fixture was mounted was fairly wide. If it was smaller, there would be more light towards the rear of the fixture, but it would not be equivalent to that of the current pathway lights. When the incandescent turns off, the LED would remain on for low level lighting. Figure 10 shows the ground illuminance map for the LED hybrid fixture with only the LED light on. The scale was adjusted in order to see the lighting level differences and does not correlate with the scale in Figure 9. Southern California Edison Page 9 of 13

10 Figure 10: LED Ground Illuminance Map for Hybrid LED Pathway Light For the National Park Service, it is not recommended to replace the existing fixtures with the LED hybrid pathway light. The occupancy coverage pattern is not sufficient for outdoor ranges and does not provide general lighting and marker lighting equivalent to that of the current fixture. RECOMMENDATIONS For applications such as this, it is recommended that the current occupancy sensor be replaced with one that has a wider coverage pattern and longer range. In straight pathways, the sensor would not turn the lights on until one is approximately two feet away from the fixture. One possible occupancy sensor replacement could be the sensor from the hotel night light, because it was designed to be mounted about 4 feet high with a spread pattern that looks out and down. Figure 11 shows the manufacturer s occupancy sensor coverage pattern specification sheet for the hotel night light. Southern California Edison Page 10 of 13

11 Figure 11: Manufacturer s Occupancy Sensor Specification Sheet The occupancy range shown here is for ideal situations which may not be the case for the actual application. A test was conducted to see its actual coverage pattern. Figure 12 shows the measured coverage pattern of the hotel night light when walking directly toward it at various angles. Southern California Edison Page 11 of 13

12 Figure 12: Detection Point Locations While Walking Towards the Night Light From the measured data, this sensor has wider coverage pattern and longer reach. If there is a six-foot wide path, the center of the path would be three feet from the sensor. Figure 13 shows the detection points for both sensors with an orange line to represent the center of the path. Southern California Edison Page 12 of 13

13 Figure 13: Detection Point Locations for Both Sensors If a person walks down the center of the path along the orange line, the hotel night light sensor would detect the occupant at about six feet away. This is marked by a red dot in the diagram. The pathway light occupancy sensor would detect the person at a distance of four feet instead, represented by a green dot. It can be seen that the hotel night light occupancy sensor would provide better coverage than that of the occupancy sensor of the hybrid LED pathway light in this situation. Southern California Edison Page 13 of 13